Re: >= and <= for string comparison

[Peng Yu]

On 1/16/23, Ruiyang Peng <rain@ryp.intirain.cc> wrote:
> On 2023/1/17 7:55, Peng Yu wrote:
>> OK. I never thought about that.
>>
>> It is functionally equivalent, but not as readable as >= and <=.
>>
>> For the same logic, for arithmetic operators, we could use ((! (x< y)
>> )) and ((! (x > y) )). But there are still >= and <= for arithmetic
>> operators. Why don't have >= and <= for strings?
>>
>> On 1/16/23, Kerin Millar <kfm@plushkava.net> wrote:
>>> On Mon, 16 Jan 2023 12:01:12 -0600
>>> Peng Yu <pengyu.ut@gmail.com> wrote:
>>>
>>>> string1 < string2
>>>>                True if string1 sorts before string2 lexicographically.
>>>>
>>>>         string1 > string2
>>>>                True if string1 sorts after string2 lexicographically.
>>>>
>>>> According to the manual, >= and <= are not available for string
>>>> comparison. But if >= and <= are available for arithmetic expression.
>>>> Why >= and <= can not be introduced for string comparison? Currently,
>>>> as a walkaround, I have to use > and = for >=, and < and = for <=. It
>>>> is rather cumbersome to write bash code in this way.
>>> This is not a response to the question itself but the penultimate
>>> sentence
>>> isn't true. [[ ! str1 < str2 ]] and [[ ! str1 > str2 ]] would also do.
>>>
>>> --
>>> Kerin Millar
>
> I think it would be simple to add support for >= and <=, and would also
> unify operations on strings with arithmetic operations.  I haven't
> figured out what problem this could cause just yet.  I think the biggest
> reason why bash didn't add this is that it's not very useful.

It could be a reason.

But it takes more effort to find out that it is not available when it
is counter-intuitive not to provide string operations but arithmetic
operations. In this sense, it is better to add >= <= for string
comparisons to make the interface uniform. After all, it should be
straightforward to add support of >= and <= on the current framework.

-- 
Regards,
Peng